Abstract Aerosol inhalation therapy is one of the cornerstones of respiratory therapy. The size of airborne particles determines their deposition pattern within the lungs and therefore, the efficacy of inhalation therapy. In this Phase 1 SBIR project, BridgeSource Medical (BSM) proposes to develop a breath-adaptive nebulizer with variable aerosol droplet sizes and actuation times. This can be used to administer precise doses of pharmaceutical drugs to the systemic circulation with much greater efficiency than currently available aerosol delivery devices like small-volume adaptive aerosol delivery (AAD) nebulizers that require strict patient breath timing, but do not vary droplet size. The nebulizer would be particularly beneficial in the administration of medications to treat elderly patients with respiratory conditions such as pulmonary hypertension, where long treatment times and strict requirements on patient breathing lead to poor compliance. The ultimate goal will be to develop a clinical tool that would be approved by the Food and Drug Administration (FDA) as an effective system to nebulize several drug formulations targeted for patients who cannot easily comply with strict breathing maneuvers, such as the those with advanced lung disease.